Methanol fuel cells promise to provide efficient and low-cost electrical current from methanol without burning the fuel. Therefore, pollution from combustion is not created by the use of such fuel cells. The fuel cells are more than twice as efficient as gasoline engines; they run cool, without the need for insulation and structural reinforcement; and rely on a relatively inexpensive fuel. The methanol fuel cells which were designed initially produced about 5 kW, running up to 200 continuous hours, and up to 3,000 intermittent hours, without suffering any loss in performance. The goal is to produce units which can generate up to 40 kW, which would be enough to power a full-size automobile, and which can run for at least 1,000 continuous hours.
The biplate is a two-sided component which is placed between the membrane electrode assemblies (MEA) in a fuel cell stack. One side of the biplate is oriented to face the anode of one MEA, and the other side of the biplate is oriented to face the cathode of another MEA. The biplate provides electrical contact to both of the MEA. It also acts to separate air or oxygen provided to the cathode of one MEA and the fuel provided to the anode of the other MEA. As such it forms part of the fuel cell compartment containing either fuel or air.
The endplate is a fuel cell component which forms part of the last fuel cell compartment in a stack, if a stack is present. If the cells are not stacked, the endplate is simply a wall of the fuel cell. The endplate provides electrical contact between an electrode of the fuel cell and the electrical load which spans the fuel cell or stack of fuel cells. The endplate is simply a single-ended biplate. Thus, both fuel cell components, biplates and endplates, are electrically conductive elements. These plates were typically formed of machined graphite.
Fuel cell components designed for use in hydrogen/air fuel cells needed to be both thermally conductive and electrically conductive. Hydrogen/air stacks could only release the heat generated internally through the stack material. Prior systems often used cooling plates inserted between biplates for the specific purpose of withdrawing heat from the stack in such fuel cells.
At this time, cost is the major factor limiting methanol fuel cell commercialization. An important component of the total cost of methanol fuel cells is the machined graphite biplates and endplates used in conventional cells. This material is relatively expensive, representing up to one third of the cost of a fuel cell. It is also relatively heavy. The weight of these components in fuel cells makes up a significant fraction of the total weight of the fuel cell.